Which brings me to this, where when I try to delete a payment method which does not work and add a new one, I get this: Can't delete a payment method when transactions are in process.

Which transaction? Which transaction is in process? I'm on the free plan.

The payment methods don't work.

Let's go over to the Cloudflare Billing page as suggested by this Cloudflare Doc page here: developers.cloudflare.com/billing/upda...

Note the part in the image where it suggests to deleting a payment method before adding a third one.

OK I will delete my secondary payment method & add a new one.

This image is in Cloudflare's Domain Renewal page for my domain which shows that the domain has expired and suggests me to update my payment method in order to fix the registration.....

Okay cool! Will do that.